* lisp/gnus-sum.el (gnus-data-set-header): Expand `setf'

appears in the backquoted form.

diff --git a/lisp/gnus-sum.el b/lisp/gnus-sum.el
index 25801c6..b9dba33 100644 (file)
--- a/lisp/gnus-sum.el
+++ b/lisp/gnus-sum.el
@@ -2112,7 +2112,7 @@ The following commands are available:
   `(nth 3 ,data))
 
 (defmacro gnus-data-set-header (data header)
-  `(setf (nth 3 ,data) ,header))
+  `(setcar (nthcdr 3 ,data) ,header))
 
 (defmacro gnus-data-level (data)
   `(nth 4 ,data))